Evaluation of angiogenesis in canine mammary tumors by quantitative platelet endothelial cell adhesion molecule immunohistochemistry

Angiogenesis was evaluated by immunohistochemistry for platelet endothelial cell adhesion molecule (CD31) in a series of benign and malignant canine m ammary neoplasms. Computer image analysis was used to measure the intratumo ral microvessel density (number of microvessels per square millimeter) and the area and perimeter of immunolabeled vascular structures. A higher intra tumoral microvessel density and lower values for area and perimeter were fo und in malignant neoplasms compared with benign tumors and among the malign ant tumors, in less differentiated phenotypes and in more anaplastic histol ogical types (solid and squamous carcinomas), most of which had metastasize d. These findings are consistent with an increase in angiogenesis in multis tage neoplasia. Therefore, in more anaplastic malignant neoplasms, numerous but small and often malformed new Vessels can be identified. The correlati on of angiogenesis data with differentiation grade and histological type of mammary neoplasms is consistent with the findings in human medicine and de monstrates that angiogenesis can also have a prognostic value in veterinary medicine.